The Dr. Miriam and Sheldon G. Adelson Medical Research Foundation in turn disseminated most of the money to more than a dozen hospitals, laboratories and universities for medical research into cancer, as well as inflammatory bowel disease and neural repair and rehabilitation, IRS documents indicate.

Donation recipients in 2011 include The Rockefeller University in New York ($500,000), Tel Aviv University in Israel ($457,608), Harvard Medical School ($280,328), the UCLA Foundation ($280,000) and Johns Hopkins University ($200,000).

Such money is a fraction of the more than $93 million the Adelsons bestowed on pro-Republican super PACs during 2011 and 2012, ahead of last year’s national elections. Nearly half of that amount went to a pair of conservative powerhouses: American Crossroads, the super PAC co-founded by Karl Rove received $23 million, while pro-Mitt Romney super PAC Restore Our Future took in $20 million.

But Adelson’s medically focused giving further illuminates the complex and diverse donation habits of the nation’s top super PAC patron, whose Las Vegas Sands gambling empire has made him one of the world’s most wealthy individuals.

Consider that the Adelsons also operate a much larger, separate nonprofit foundation, the Adelson Family Foundation, that’s contributed $191 million to primarily pro-Israel and Jewish cultural, educational and research organizations. Most went to Birthright Israel, a charity that offers free 10-day trips to Israel to Jews between age 18 and 26.

The educational foundation’s latest filing with the IRS shows it raised more than $8 million from July 2011 to June 2012, although it doesn’t state where the money came from. The organization reported more than $48 million in assets but more than $49 million in liabilities, leaving it about $800,000 in the red through last June, according to its IRS filing.

Meanwhile, the Dr. Miriam and Sheldon G. Adelson Charitable Trust, which is also a 501(c)(3) nonprofit, had nearly $80 million in assets through the end of 2011, IRS filings show. Most of the more than $19.4 million it spent that year went to other Adelson-controlled foundations.

The Las Vegas-based Dr. Miriam and Sheldon G. Adelson Clinic for Drug Abuse Treatment & Research Inc., likewise organized as a nonprofit charity, reported about $133,000 in net assets through the end of 2011, IRS records show.

As for the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation, it’s taken in about $58.9 million — mostly from the Adelsons themselves — from its formation in mid-2006 through the end of 2011. It spent about $58.5 million during the same time period, according to IRS records.

After spending more than $24.4 million in 2007, the research foundation’s giving has waned, dropping to $4.2 million in 2010 before inching up in 2011.

Sheldon Adelson’s office in Las Vegas directed questions to Kenneth Fasman, the foundation’s chief science officer, who declined to comment on the Massachusetts-based foundation’s work and finances during 2012 and 2013.

The foundation’s website offers some general details on its purpose and mission.

“Instead of funding individual experiments that cautiously advance progress, we ask investigators who receive funding to interact with peers at many institutions within the context of creative and risk-taking approaches that may yield much more than the incremental progress engendered by many funding organizations,” it states.

Primary Source dove into developments in the post-Citizens United world of money in politics. It featured original, entrepreneurial reporting by Center staff, as well as examinations of primary source documents.